Is it Delirium or is it Dementia?

 Delirium is defined as a sudden severe confusion and rapid changes in brain function that happen with physical and mental illness. It is a clinical syndrome or a set of symptoms and not a disease. It is one of the oldest forms of mental disorder that has been known in medical history. Studies indicate that 32-67% of delirious patients go into hospital undiagnosed. Delirium can be caused by some factors, the most common ones are critical illnesses like sepsis, fever, poisons, and hypoxia.

Withdraw from drugs like alcohol and benzodiazepines. We also see delirium in people who have trauma to the head or brain diseases like cancer. Delirium can also be a result of neurological and metabolic disorders. The duration delirium is dependent on the cause, in some cases, it persists for months and may result in a permanent decline in cognitive function.  People suffering from delirium are at risk of developing dementia in later years. Types of delirium include hyperactive, hypoactive and Mixed delirium

The central core features of delirium are,

  • Disturbance in consciousness
  • Change in cognition ( memory disturbance) or perpetual disturbances
  • Onset can be hours to days
  • The behaviour can be overactive or underactive, bewildered, evasive, aggressive, withdrawn and sleep is often disturbed
  • Thinking maybe slow and muddled but the content is usually complicated.
  • Speech may be rumbling
  • Delusion and visual hallucination

Common causes of delirium and agitation

  • Infection – urinary tract infection, pneumonia, and septicemia
  • Cardiac – Myocardial infarction or heart attack
  • Mechanical – environmental barriers to movement, restrains and wheelchairs.
  •  Gastrointestinal – Constipation/diarrhoea
  • Environment – changes to the environment.

Throughout the western world, delirium is the most common complain complaint among psychiatric patients. The pathophysiology is not adequately understood, but the cause is thought to be as a result of many pathogenic microorganisms that impairs cerebral oxidative metabolism. This is results in the reduction in the synthesis of neurotransmitters like acetylcholine. Delirium may also stress related.

The clinical diagnosis is made by the clinical history. Examination, relevant investigative tools like (blood and CT head).   There is also a need to establish previous functional and cognitive changes. The clinical diagnostic tool used include; abbreviated mental test score which is 10 questions that assess cognitive function. Another clinical tool that can be used is a mini-mental status examination which is brief 30 point questionnaire test to screen for cognitive function.

The current best practice guidelines in Australia are to; treat the underlying cause and optimise condition for the brain function.  For example, make sure the patient is oxygenated and well hydrated and make sure they are receiving adequate nutrition, not in pain or constipated and not stressed. Also, provide environmental and supportive measures through reduction of bed movement, orientate through clocks, photos, glasses. Verbal and non-verbal de-escalation techniques.

Delirium Vs Dementia

preventing-delirium-in-geroforensic-population-29-638-1Slide share. come 


These are study notes and should not be used as a diagnostic tool if you or your family suspect delirium seek medical treatment straight away. 



The department of health. (2017). Patient Brochure, Delirium Retrieved from

Inouye, S. K., van Dyck, C. H., Alessi, C. A., Balkin, S., Siegal, A. P., & Horwitz, R. I. (1990). Clarifying confusion: The confusion assessment methoda new method for detection of delirium. Annals of internal medicine113(12), 941-948.

Ely, E. W., Shintani, A., Truman, B., Speroff, T., Gordon, S. M., Harrell Jr, F. E., … & Dittus, R. S. (2004). Delirium as a predictor of mortality in mechanically ventilated patients in the intensive care unit. Jama291(14), 1753-1762.

Photo of the brain taken from –


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